Image analysis – Histogram processing – For setting a threshold
Patent
1988-09-28
1990-02-13
Boudreau, Leo H.
Image analysis
Histogram processing
For setting a threshold
3582612, 358456, 358462, 382 52, G06K 936
Patent
active
049013637
ABSTRACT:
A system is disclosed for arithmetically compressing bi-level data of an image by sampling history pels, which are adjacent pels to a current pel to be processed, and pels so separated from the adjacent pels as to adapt to a period of a dither matrix for a dither image. From the sampled pels it is determined whether the sampled image has a dither dominant image pattern or a text-graphic dominant image pattern and an appropriate signal is generated, a first signal representing that the image has the dither dominant image pattern, a second signal representing that the image has the text-graphic dominant image pattern, and a third signal representing that the image is not classified as either of these image patterns. The first, second and third signals are applied to an up-down counter which accumulates the occurrences of the signals to produce, when the accumulated value exceeds an upper threshold or a lower threshold, a control signal for selectively switching access to first and second statistical tables, which store, at each entry, the more probable symbol and the probability of the less probable symbol for the image of the text-graphic image and the dither image, respectively.
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Boudreau Leo H.
Dowd Thomas P.
International Business Machines - Corporation
Mancuso Joseph
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